Perpendicular magnetic recording has been developed in part to achieve higher recording density than is realized with longitudinal recording devices. A PMR write head typically has a main pole layer with a small surface area (pole tip) at an ABS, and coils that conduct a current and generate a magnetic flux in the main pole such that the magnetic flux exits through the pole tip and enters a magnetic medium (disk) adjacent to the ABS. Magnetic flux is used to write a selected number of bits in the magnetic medium and typically returns to the main pole (MP) through two pathways including a trailing loop and a leading loop. The trailing loop is comprised a trailing shield structure with a front side at the ABS, an uppermost (PP3) trailing shield that arches over the driving coil and connects with a top yoke (TY). The TY adjoins a top surface of the MP above a back gap connection (BGC). The trailing loop is also known as the top driving loop and delivers magnetic flux to the MP tip to write positive and negative field into magnetic media. The leading loop has a leading shield with a side at the ABS and that is connected to a return path (RTP) having a front side recessed from the ABS. The RTP extends back to the BGC and enables magnetic flux in the leading loop pathway to return from the leading shield at the ABS and through the BGC to the MP for faster saturation speed, better adjacent trace interference (ATI) and enhanced wide area track erasure (WATE) potential.
Dual write shield (DWS) designs that feature complete leading and trailing loops were invented for adjacent track erasure (ATE) improvement by reducing stray field in side shields and in the leading shield. Accordingly, a PMR head has a great advantage over LMR in providing higher write field, better read back signal, and potentially much higher areal density. With the growing demand for cloud storage and cloud-based network computing, high and ultra high data rate recording becomes important for high-end disk drive applications.
To achieve areal density in a HDD beyond 2 terabytes per platter (TBPP) for conventional PMR, dual writer designs have been proposed where the better of the two writers is determined during back end testing, and then the better writer is paired with a suspension and integrated in a HGA. However, there is a need to continually decrease writer-writer spacing in order to reduce RWO and meet ADC requirements, and to provide magnetic core shapes that are compatible with various pathways for magnetic flux to return to the main pole layer. Therefore, an improved dual PMR writer design is needed to enable additional reduction in WWS without increasing the complexity of the fabrication process.